Indefinitely reusable bags, packets and any other similar components used for delivery of confidential documents or any other kind of objects requiring said confidentiality and using a zipper or the like as a fastening means, the zipper providing said reusable nature are already known.
To achieve delivery inviolability, seals conveniently attached to the bag or component being used, capable of receiving and attaching the zipper's tongue with an easily engageable snap fastener, which disengagement inescapably however brings about the seal breakage and proof of a tampered fastener are already known.
In this connection, the Spanish invention patent no. 421 407 discloses a seal made up in a base body, conveniently attached to the bag or component being used and provided with a prismatic protuberance closely going through a window. operatively made in the zipper's tongue, this protuberance being jutted out with respect to said tongue and incorporating a side window with access to its hollow inside, wherein the proper seal part itself made up with a kind of arrow tip, capable of penetration, by elastic strain, in the cavity of said small box is engageable, but is unable to be subsequently drawn out without breakage of the branches making up said arrow tip.